1st @Plebeian Market (easiest to start with): i). Use desktop for that : https://plebeian.market), you'll need a signer extension (try for example Nos2X or Flamingo ; 1st login with your Nostr 'profile' and then use it to get onto Plebeian ; btw. it will be useful for many other Nostr desktop platforms). ii). Through Dashboard start adding products/collection of products etc. - this part is super easy